An e-Health Intervention to Improve Symptom Burden and Health-Related Quality of Life among Hispanic Women Completing Active Treatment for Breast Cancer Abstract Among Hispanics, the largest and fastest growing ethnic minority group in the U.S., cancer is the leading cause of death whereas cardiovascular disease is the leading cause of death for African Americans and non- Hispanic Whites (NHWs). Hispanics also experience substantially lower rates of 5-year cancer-specific survival relative to non?Hispanic Whites (NHWs). Hispanic cancer patients in the U.S. also report significantly worse cancer-related symptom burden and health-related quality of life (HRQOL) than NHWs, even after adjusting for socioeconomic factors. Despite this, very few randomized, intervention studies have specifically targeted cancer-related symptom burden and HRQOL outcomes among Hispanic women, especially during the period at the end of active treatment which is a critical period to intervene to provide skills and tools to assist with this transition. Innovative approaches to providing interventions such as Smartphone technology are especially important for this patient population. Ubiquitous Smartphone use among ethnic minorities in the US provide a unique opportunity to implement a pragmatic technology- and evidence-based psychosocial intervention that overcomes some access to care barriers as well as time and logistical constraints. Furthermore, given that Hispanics own Smartphones and seek health information online from a mobile device at similar or higher rates than other groups in the U.S., Smartphone interventions offer an opportunity to overcome obstacles to accessing resources and services that can be culturally informed and provide skills to improve symptom burden and HRQOL. This study aims to create and evaluate Mi Gua (My Guide), a culturally informed eHealth psychoeducational and psychosocial intervention for English or Spanish-speaking Hispanic women completing treatment for breast cancer. Mi Gua is grounded in evidence-based paradigms to improve our Primary Outcomes: Cancer-Related Symptom Burden and HRQOL and our Secondary Outcomes: usability and markers of Mi Gua use. We propose a two-phase study to develop our Smartphone-based intervention that can be disseminated to cancer survivors at a relatively low cost. We will use innovative methodology; MOST framework that will allow us to achieve both optimization and evaluation of Mi Gua by determining which single components or combination of components in Mi Gua affect our outcomes. Study components (one component on breast cancer psychoeducation, two psychosocial evidence-based components relevant to Hispanic BCS) will be paired with personal tele-coaching among BCS. Our Aims are: Aim 1:(Phase 1): Create Mi Gua, an eHealth intervention designed to improve cancer-related symptom burden and HRQOL. Aim 2: (Phase 2): Optimize components for Mi Gua through a 9-week randomized trial to evaluate three evidence- based intervention components relevant to Hispanic BCS. It is hypothesized that each single intervention component will improve cancer-related symptom burden and HRQOL and that combined intervention components will have a greater effect on our outcomes than single components.